We derive an expression for the phase shift of an atom interferometer in a gravitational field taking into account both the finite duration of the light pulses and the effect of a small perturbing potential added to a stronger uniform gravitational field, extending the well-known results for rectangular pulses and at most quadratic potentials. These refinements are necessary for a correct analysis of present day high resolution interferometers.
The theory of stimulated Raman adiabatic passage in a three-level Lambda-scheme of the interaction of an atom or molecule with light, which takes the nonadiabatic processes at the beginning and the end of light pulses into account, is developed.
High-order inertial phase shifts are calculated for time-domain atom interferometers. We obtain closed-form analytic expressions for these shifts in accelerometer, gyroscope, optical clock and photon recoil measurement configurations. Our analysis in
cludes Coriolis, centrifugal, gravitational, and gravity gradient-induced forces. We identify new shifts which arise at levels relevant to current and planned experiments.
The nitrogen vacancy (NV) color center in diamond is an enormously important platform for the development of quantum sensors, including for single spin and single molecule NMR. Detection of weak single-spin signals is greatly enhanced by repeated seq
uences of microwave pulses; in these dynamical decoupling (DD) techniques, the key control parameters swept in the experiment are the time intervals, $tau$, between pulses. Here we show that, in fact, the pulse duration offers a powerful additional control parameter. While previously, a non-negligible pulse-width has been considered simply a source of experimental error, here we elucidate the underlying quantum dynamics: we identify a landscape of quantum-state crossings which are usually closed (inactive) but may be controllably activated (opened) by adjusting the pulse-width from zero. We identify these crossings with recently observed but unexpected dips (so called spurious dips) seen in the quantum coherence of the NV spin. With this new understanding, both the position and strength of these sharp features may be accurately controlled; they co-exist with the usual broader coherence dips of short-duration microwave pulses, but their sharpness allows for higher resolution spectroscopy with quantum diamond sensors, or their analogues.
Atom interferometers are a useful tool for precision measurements of fundamental physical phenomena, ranging from local gravitational field strength to the atomic fine structure constant. In such experiments, it is desirable to implement a high momen
tum transfer beam-splitter, which may be achieved by inducing quantum resonance in a finite-temperature laser-driven atomic gas. We use Monte Carlo simulations to investigate these quantum resonances in the regime where the gas receives laser pulses of finite duration, and demonstrate that an $epsilon$-classical model for the dynamics of the gas atoms is capable of reproducing quantum resonant behavior for both zero-temperature and finite-temperature non-interacting gases. We show that this model agrees well with the fully quantum treatment of the system over a time-scale set by the choice of experimental parameters. We also show that this model is capable of correctly treating the time-reversal mechanism necessary for implementing an interferometer with this physical configuration.
Cold-atom interferometers commonly face systematic effects originating from the coupling between the trajectory of the atomic wave packet and the wave front of the laser beams driving the interferometer. Detrimental for the accuracy and the stability
of such inertial sensors, these systematics are particularly enhanced in architectures based on spatially separated laser beams. Here we analyze the effect of a coupling between the relative alignment of two separated laser beams and the trajectory of the atomic wave packet in a four-light-pulse cold-atom gyroscope operated in fountain configuration. We present a method to align the two laser beams at the $0.2 mu$rad level and to determine the optimal mean velocity of the atomic wave packet with an accuracy of $0.2 textrm{mm}cdottextrm{s}^{-1}$. Such fine tuning constrains the associated gyroscope bias to a level of $1times 10^{-10}~textrm{rad}cdottextrm{s}^{-1}$. In addition, we reveal this coupling using the point-source interferometry technique by analyzing single-shot time-of-flight fluorescence traces, which allows us to measure large angular misalignments between the interrogation beams. The alignment method which we present here can be employed in other sensor configurations and is particularly relevant to emerging gravitational wave detector concepts based on cold-atom interferometry.
A. Bertoldi
,F. Minardi
,M. Prevedelli
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(2018)
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"Phase shift in atom interferometers: corrections for non-quadratic potentials and finite-duration laser pulses"
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Francesco Minardi
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